Malaria is a mosquito-borne disease caused by Plasmodium parasites and represents one of the greatest public health challenges worldwide, especially in sub-Saharan Africa. Accomplishments in malaria control during the past two decades have been significant, but elimination remains the ultimate objective. Vector surveillance – that is, monitoring the mosquito vector populations to understand the biology and distribution of these pests – forms the cornerstone of the path to malaria elimination. The Third International Course on Vector Surveillance, as documented by the insights shared here, views vector surveillance through the lens of ongoing efforts to eliminate malaria.
Understanding Vector Surveillance
Systematic testing of mosquitoes and the collection of excellent data about them in different locales not only clarify areas of risk but also help identify blind spots in larvae habitats. Ultimately, this information informs vector control activities. In this context, vector surveillance involves:
- Species identification: Identification of mosquito species by their morphometric features and by detection of the larvae, pupae, and adults is important. Not all mosquito species transmit malaria, so it is critical to know which species are present in a given area. Surveillance is important for this.
- mosquito surveillance: covering areas where there are mosquito breeding sites, assessing density and distribution In terms of density, which refers to the number of mosquitoes per area, a higher density usually indicates more malaria transmission.
- Behavioral Studies: Analyzing mosquito feeding patterns, preferred times of day, preferences for humans versus animals, and breeding times provides insights into malaria transmission, helping to determine the most effective targets for intervention.
- Resistance Monitoring: surveillance includes monitoring mosquito populations for insecticide resistance, to ensure that vector control measures remain effective.
The Third International Course on Vector Surveillance
The Zero-Malaria Acceleration Plan took place in Vienna from 6-16 November 2018. In particular, it served as the third international course on vector surveillance for malaria control, aimed at training, information sharing, and knowledge exchange among experts, researchers, and practitioners from all over the world. Moreover, this course provided a forum to share and explore innovative approaches and best practices for vector surveillance. Consequently, these are the key takeaways from it:
1. Integration of Modern Technologies
The integration of vector surveillance into modern technology was a major emphasis, given how important advances in technology have revolutionized vector surveillance, with enhanced precision and efficiency in data collection and analysis. Vital technological innovations presented in the course were:
- Geographic Information Systems (GIS): GIS is a technology that can map mosquito populations and the places they breed, making it easier to discern high-risk areas and better target interventions.
- Remote Sensing: Satellite imagery and remote sensing have information on the environmental conditions conducive to mosquito breeding, for example referring to water bodies and vegetation.
- Emerging molecular tools include the use of PCR (polymerase chain reaction) and DNA barcoding to identify species of mosquitoes and to discover malaria parasites in populations of mosquitoes.
- Smart Traps: modern mosquito traps combined with sensors and data loggers provide real-time data on mosquito density and species composition to improve the precision of surveillance.
2. Community-Based Surveillance Programs
Community engagement was emphasized as an important feature of effective vector surveillance programs. Involving local communities in surveillance efforts enhances data collection and community support for malaria control measures. Approaches to do this include:
- Training Community Health Workers: Training local health workers and citizen volunteers to identify breeding sites and monitor mosquito populations helps to improve the spatial and temporal coverage and accuracy of surveillance.
- Community Education: Educating the public on the importance of looking for vectors and recording data will help volunteers engage and contribute to vector surveillance.
- Citizen science: Making citizens a part of the process of reporting sightings and breeding sites for mosquitoes helps collect data and builds a sense of ownership and responsibility for controlling malaria.
3. Collaborative Approaches
The focus of the course was on the network—specifically, the need for coordination among the various stakeholders involved in vector surveillance. In particular, it requires excellent collaboration between government ministries, academic and medical research institutes, non-governmental organizations (NGOs), and international bodies to achieve malaria elimination. Key points of collaboration include:
- Data sharing: Pooling data on malaria transmission (and findings from malaria control and treatment) from different institutions and countries increases overall knowledge and promotes coordinated intervention.
- Joint Research Initiatives: Investigations that invoke expertise from entomology, epidemiology, and public health provide a much-needed synergy of research and development.
- Policy Development: Coordination of a group of people to develop and implement policies/guidelines for vector surveillance is essential to achieve consistency and efficiency in malaria control activities.
4. Addressing Challenges and Gaps
The course also tackled implementation gaps and areas of challenge in vector surveillance that must be addressed to strengthen elimination efforts:
Innovative funding mechanisms and resource allocation are needed to overcome restriction issues. Resource constraints: Lack of funds and resources, notably including personnel and infrastructure, can limit the effectiveness and coverage of vector surveillance programs. Funding and Assessment: Before allocating additional funds, systematic assessments of the willingness to pay for vector control are necessary, along with innovative funding mechanisms and resource allocation strategies.
- Data Quality and Standardization: First and foremost, all data must undergo quality assurance and standardization to ensure consistent, accurate, and effective analysis and decision-making. To achieve this, implementing standardized protocols and data management systems is essential. Moreover, these measures will enhance the reliability of the data and support better outcomes in our initiatives.
- Resistance Management: Since insecticide resistance is a persistent issue once it develops, surveillance programs must monitor resistance early in their implementation and prepare strategies to address it when it arises.
Impact of Vector Surveillance on Malaria Elimination
The Third International Course was decisive in making plain the influence that vector surveillance exerts upon malaria control and elimination efforts by identifying the following outcomes.
- Targeted interventions: Vector surveillance supplies the information needed to target interventions more effectively: for example, it tells us where to use insecticide-treated nets and indoor residual spraying.
- Early Outbreak Detection: Early detection of shifts in mosquito populations and malaria transmission helps contain outbreaks more effectively.
- Evidence-Based Policies: evidence-based policies are crucial, as surveillance data informs policy decisions for malaria control. Specifically, this data helps prioritize resource allocation and ensures the implementation of targeted and effective strategies.
- Surveillance: Tracking mosquito populations and the number of people contracting malaria helps to measure the success of malaria elimination efforts as they unfold and adjust strategies as necessary.
Vector surveillance forms a central pillar of malaria elimination strategies, but can it be enhanced? Vector surveillance generates key data on malaria vector populations, which will inform national malaria control strategies and will be critical for evaluating the success of elimination programs. At this point, during the Third International Course on Vector Surveillance, we focused on advances in vector surveillance. Notably, entomologists have received significant support from new technologies, community involvement, collaborations, and the use of epidemiological methods to address the challenges faced over the past decade. Ultimately, the gains we will reap from the lessons learned by entomologists over the past 20 years of vector surveillance will greatly accelerate progress toward elimination and positively influence the health of many Africans.
